Electric working machine

ABSTRACT

An electric working machine may include a support rod, a head unit, a position fixing mechanism, and a resistance member. The support rod may extend in a front-rear direction and include an attachment portion located at a front end of the support rod. The head unit may include a front tool, a motor configured to drive the front tool, and a head housing supporting the front tool and coupled to the attachment portion rotatably about a rotation axis. The position fixing mechanism may be configured to fix a rotation position of the head unit with respect to the support rod. The resistance member may be interposed between the attachment portion and the head housing with respect to a direction perpendicular to the rotation axis. The resistance member may be configured to provide a resistance force against rotation of the head unit with respect to the support rod.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No.2019-132846 filed on July 18, the entire contents of which are herebyincorporated by reference into the present application.

TECHNICAL FIELD

This disclosure herewith relates to an electric working machine.

BACKGROUND

Japanese Patent Application Publication No. 2002-58341 describes aworking machine. The working machine comprises a support rod, a headunit, and a position fixing mechanism. The support rod extends in afront-rear direction. The support rod comprises an attachment portionlocated at a front end thereof. The head unit is configured to berotatable with respect to the support rod. The head unit comprises afront tool, a motor configured to drive the front tool, and a headhousing coupled to the attachment portion rotatably about a rotationaxis. The position fixing mechanism is configured to fix a rotationposition of the head unit with respect to the support rod.

SUMMARY

When the head unit rotates with respect to the support rod in the aboveworking machine, the head unit may be sharply bent toward the supportrod. Since an operator is gripping the support rod when causing the headunit to rotate with respect to the support rod, if the head unit issharply bent toward the support rod, the operator might inadvertentlyhave his/her hand caught therebetween. The disclosure herein disclosesart that can prevent a head unit from being sharply bent toward asupport rod.

The disclosure herein discloses an electric working machine. Theelectric working machine may comprise a support rod, a head unit, aposition fixing mechanism, and a resistance member. The support rod mayextend in a front-rear direction and comprise an attachment portionlocated at a front end of the support rod. The head unit may comprise afront tool, a motor configured to drive the front tool, and a headhousing supporting the front tool and coupled to the attachment portionrotatably about a rotation axis. The position fixing mechanism may beconfigured to fix a rotation position of the head unit with respect tothe support rod. The resistance member may be interposed between theattachment portion and the head housing in a direction perpendicular tothe rotation axis. The resistance member may be configured to provide aresistance force against rotation of the head unit with respect to thesupport rod.

According to the above configuration, the resistance member provides theresistance force when the head unit rotates with respect to the supportrod, thus the rotation of the head unit with respect to the support rodis suppressed. This prevents the head unit from being sharply benttoward the support rod.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a working machine 2 of a firstembodiment.

FIG. 2 is a cross-sectional view of a head unit 20 of the workingmachine 2 of the first embodiment.

FIG. 3 is a top view of the head unit 20 of the working machine 2 of thefirst embodiment.

FIG. 4 is a perspective view of an attachment portion 14 of the workingmachine 2 of the first embodiment.

FIG. 5 is a cross-sectional view of an area around a rod portion 12 of asupport rod 10, a position fixing mechanism 88, and a rotation unit 56of the working machine 2 of the first embodiment.

FIG. 6 is a perspective view of a tension member 94 and an insertionmember 90 of the working machine 2 of the first embodiment.

FIG. 7 is a cross-sectional view of an area around the rotation unit 56of the working machine 2 of the first embodiment, with a shaft 90 b ofthe insertion member 90 inserted in an intermediate opening 78 c.

FIG. 8 is a cross-sectional view of the area around the rotation unit 56of the working machine 2 of the first embodiment, with the shaft 90 b ofthe insertion member 90 inserted in a proximal opening 78 b.

FIG. 9 is a cross-sectional view of the area around the rotation unit 56of the working machine 2 of the first embodiment, with the shaft 90 b ofthe insertion member 90 inserted in a fully-bent positioning opening 82.

FIG. 10 is a perspective view of the working machine 2 of the firstembodiment, with the shaft 90 b of the insertion member 90 inserted inthe proximal opening 78 b.

FIG. 11 is a perspective view of the working machine 2 of the firstembodiment, with the shaft 90 b of the insertion member 90 inserted inthe fully-bent positioning opening 82.

FIG. 12 is a side view of the attachment portion 14 and a positionsensor 104 of the working machine 2 of the first embodiment, with theshaft 90 b of the insertion member 90 inserted in the intermediateopening 78 c.

FIG. 13 is a side view of the attachment portion 14 and the positionsensor 104 of the working machine 2 of the first embodiment, with theshaft 90 b of the insertion member 90 inserted in the fully-bentpositioning opening 82.

FIG. 14 is a side view of the working machine 2 of the first embodiment,with a left grip housing 106 a and a left rear housing 126 a removed.

FIG. 15 is a perspective view of a trigger 108, a detection sensor 110,a lever 114, and a presence sensor 116 of the working machine 2 of thefirst embodiment.

FIG. 16 is a cross-sectional view of an area around the presence sensor116 of the working machine 2 of the first embodiment, with the workingmachine 2 seen from the rear.

FIG. 17 is a cross-sectional view of an area around a control unit 128of the working machine 2 of the first embodiment, with the workingmachine 2 seen from the rear.

FIG. 18 is a rear plan view of the working machine 2 of the firstembodiment.

FIG. 19 is a cross-sectional view of an area around a rotation unit 56of a working machine 2 of a second embodiment, with a shaft 90 b of aninsertion member 90 inserted in an intermediate opening 78 c.

DETAILED DESCRIPTION

Representative, non-limiting examples of the present disclosure will nowbe described in further detail with reference to the attached drawings.This detailed description is merely intended to teach a person of skillin the art further details for practicing preferred aspects of thepresent teachings and is not intended to limit the scope of the presentdisclosure. Furthermore, each of the additional features and teachingsdisclosed below may be utilized separately or in conjunction with otherfeatures and teachings to provide improved electric working machines, aswell as methods for using and manufacturing the same.

Moreover, combinations of features and steps disclosed in the followingdetailed description may not be necessary to practice the presentdisclosure in the broadest sense, and are instead taught merely toparticularly describe representative examples of the present disclosure.Furthermore, various features of the above-described and below-describedrepresentative examples, as well as the various independent anddependent claims, may be combined in ways that are not specifically andexplicitly enumerated in order to provide additional useful embodimentsof the present teachings.

All features disclosed in the description and/or the claims are intendedto be disclosed separately and independently from each other for thepurpose of original written disclosure, as well as for the purpose ofrestricting the claimed subject matter, independent of the compositionsof the features in the embodiments and/or the claims. In addition, allvalue ranges or indications of groups of entities are intended todisclose every possible intermediate value or intermediate entity forthe purpose of original written disclosure, as well as for the purposeof restricting the claimed subject matter.

In one or more embodiments, an electric working machine may comprise asupport rod, a head unit, a position fixing mechanism, and a resistancemember. The support rod may extend in a front-rear direction andcomprise an attachment portion located at a front end of the supportrod. The head unit may comprise a front tool, a motor configured todrive the front tool, and a head housing supporting the front tool andcoupled to the attachment portion rotatably about a rotation axis. Theposition fixing mechanism may be configured to fix a rotation positionof the head unit with respect to the support rod. The resistance membermay be interposed between the attachment portion and the head housing ina direction perpendicular to the rotation axis. The resistance membermay be configured to provide a resistance force against rotation of thehead unit with respect to the support rod.

According to the above configuration, the resistance member provides theresistance force when the head unit rotates with respect to the supportrod, thus the rotation of the head unit with respect to the support rodis suppressed. This prevents the head unit from being sharply benttoward the support rod. Thus, it is prevented that an operatorinadvertently has his/her hand caught between the head unit and thesupport rod, for example.

In one or more embodiments, a magnitude of the resistance force changes,as the rotation position of the head unit with respect to the supportrod changes.

In general, if the resistance force provided by the resistance member isconstantly large, the sharp bending of the head unit toward the supportrod can be prevented with certainty, however, the constantly largeresistance force makes it difficult for the head unit to rotate withrespect to the support rod and makes the usability deteriorated. On theother hand, if the resistance force provided by the resistance member isconstantly small, the head unit easily rotates with respect to thesupport rod, which provides improved usability, however, safety issuesrise because the head unit can be sharply bent toward the support rod.The above configuration can improve the usability while ensuring safetyfor the operator by changing the magnitude of the resistance forceprovided by the resistance member as needed.

In one or more embodiments, the rotation position of the head unit withrespect to the support rod may change between a full-bent position atwhich the head unit is fully bent toward the support rod and anoperation position at which the head unit is opened with respect to thesupport rod. The magnitude of the resistance force may increase withoutdecreasing, as the rotation position of the head unit with respect tothe support rod shifts from the operation position to the full-bentposition.

The above configuration makes it more difficult for the head unit torotate with respect to the support rod, as the head unit shifts from theoperation position toward the fully-bent position. Thus, the sharpbending of the head unit toward the support rod can more surely beprevented when the head unit rotates with respect to the support rodfrom the operation position to the fully-bent position.

In one or more embodiments, the rotation position of the head unit withrespect to the support rod may change between a full-bent position atwhich the head unit is fully bent toward the support rod and anoperation position at which the head unit is opened with respect to thesupport rod. The magnitude of the resistance force may decrease afterhaving increased, as the rotation position of the head unit with respectto the support rod shifts from the operation position to the full-bentposition.

The above configuration makes it difficult for the head unit to rotatewith respect to the support rod, as the head unit shifts from theoperation position toward a vicinity of the fully-bent position, whileit makes it easier for the head unit to rotate with respect to thesupport rod in the vicinity of the fully-bent position. Thus, theconfiguration can prevent the sharp bending of the head unit toward thesupport rod when the head unit rotates from the operation positiontoward the fully-bent position, and also can facilitate the bending ofthe head unit toward the support rod in the vicinity of the fully-bentposition.

In one or more embodiments, as the rotation position of the head unitwith respect to the support rod changes, a gap between the attachmentportion and the head unit at a position where the resistance member isinterposed may change so that the magnitude of the resistance forcechanges.

In the above configuration, the magnitude of the resistance forceprovided by the resistance member can be changed with a simpleconfiguration of changing the gap between the attachment portion and thehead unit.

In one or more embodiments, the resistance member may be constituted ofa rubber material.

In the above configuration, the resistance member can provide theresistance force without damaging or wearing the attachment portion andthe head housing.

In one or more embodiments, the front tool may comprise a cutting bladefor cutting an object.

In the above configuration, the electric working machine may be used asone of a mower, a hedge trimmer, and a chain saw.

In one or more embodiments, a working machine may comprise a support rodextending in a front-rear direction, and a head unit attached to a frontend of the support rod. The head unit may comprise a front tool, a powertransmission mechanism, a head housing, and a handle. The powertransmission mechanism may be configured to transmit power to the fronttool. The head housing may house the power transmission mechanism andmay be rotatably attached to the support rod. The handle may extendfrontward from the head housing. The handle may be configured to begripped by an operator when the head housing is rotated with respect tothe support rod. The handle may be disposed below a top portion of thehead housing in an up-down direction perpendicular to the front-reardirection in a state where the working machine is placed on a placementsurface.

According to the above configuration, in the event of an upper surfaceside of the head housing colliding against the ground surface due to theworking machine being dropped, the top portion of the head housingcollides with the ground surface first, thus the handle can besuppressed from colliding with the ground surface. As a result, damageto the handle can be prevented.

In one or more embodiments, the handle may extend obliquely toward afront lower side from the head housing in the state where the workingmachine is placed on the placement surface.

In general, application of an impact to a front end of the handle islikely to result in damage to the handle, as compared to application ofan impact to a base end of the handle. In the above configuration, thefront end of the handle is located lower than the base end of thehandle. Due to this, in the event of the upper surface side of the headhousing colliding against the ground surface due to the working machinebeing dropped, the base end of the handle collides with the groundsurface before the front end of the handle. As a result, damage to thehandle can be suppressed even when the handle collides with the groundsurface.

In one or more embodiments, the handle may be located below a lineconnecting the top portion of the head housing and a front end of thefront tool in the state where the working machine is placed on theplacement surface.

In the above configuration, in the event of the upper surface side ofthe head housing colliding against the ground surface due to the workingmachine being dropped, the top portion of the head housing and the frontend of the front tool collide with the ground surface first, thus thehandle does not collide with the ground surface. Due to this, damage tothe handle can surely be prevented.

In one or more embodiments, a length of the handle in the front-reardirection may be 25 mm or more.

When rotating the head housing with respect to the support rod, theoperator grips the handle with his/her hand. According to the aboveconfiguration, the operator can grip the handle from right side or leftside with his/her multiple fingers.

In one or more embodiments, a width of the handle in a left-rightdirection, which is perpendicular to the front-rear direction and theup-down direction, may be 20 mm or more.

When rotating the head housing with respect to the support rod, theoperator grips the handle with his/her hand. According to the aboveconfiguration, the operator can stably grip the handle from front sideor from above.

In one or more embodiments, the head housing may comprise a lower headhousing supporting the front tool and an upper head housing disposedabove the lower head housing. The handle may extend frontward from theupper head housing. The handle may be apart by 20 mm or more from thelower head housing.

When rotating the head housing with respect to the support rod, theoperator grips the handle with his/her hand. The above configurationallows the operator to insert his/her finger(s) between the front end ofthe handle and the lower head housing to grip the handle.

In one or more embodiments, an electric working machine may comprise asupport rod, a head unit, and a grip unit. The support rod may extend ina front-rear direction. The head unit may be attached to a front end ofthe support rod, and comprise a front tool and a motor configured todrive the front tool. The grip unit may be attached to a rear end of thesupport rod. The grip unit may comprise a grip housing, a detectionsensor, and a presence sensor. The grip housing may be configured to begripped by an operator. The detection sensor may be attached to the griphousing and configured to detect an on/off operation for the motor bythe operator. The presence sensor may be attached to the grip housingand configured to detect a grip by the operator on the grip housing. Thesupport rod may not penetrate through the grip housing. In a rear planview of the electric working machine, at least one of the detectionsensor and the presence sensor may at least partially overlap thesupport rod.

According to the above configuration, in the rear plan view of theelectric working machine, the entirety of the detection sensor and theentirety of the presence sensor both do not have to be disposed outsidea region overlapping the support rod. Due to this, the configuration canmake the grip housing slim, thus it can make the grip unit slim, ascompared to a configuration in which the entirety of the detectionsensor and the entirety of the presence sensor both do not overlap thesupport rod in the rear plan view of the electric working machine.

In one or more embodiments, the grip unit may further comprise a lever.The lever may be attached to the grip housing and configured to beoperated by the operator. The presence sensor may be configured todetect the grip by the operator on the grip housing when the lever isoperated.

The above configuration enables detection of the grip on the griphousing by the operator with a simple configuration.

In one or more embodiments, the electric working machine may furthercomprise a control unit disposed rearward of the rear end of the supportrod and configured to control actuation of the motor. In the rear planview of the electric working machine, the control unit may at leastpartially overlap the support rod.

According to the above configuration, in the rear plan view of theelectric working machine, the entirety of the control unit does not haveto be disposed outside the region overlapping the support rod. Due tothis, the configuration can reduce the size of the electric workingmachine in the direction perpendicular to the front-rear direction, ascompared to a configuration in which the entirety of the control unitdoes not overlap the support rod in the rear plan view of the electricworking machine.

In one or more embodiments, the front tool may comprise a cutting bladefor cutting an object.

In the above configuration, the electric working machine may be used asone of a mower, a hedge trimmer, and a chain saw.

First Embodiment

A working machine 2 of a first embodiment will be described withreference to FIGS. 1 to 18 . The working machine 2 is an electricworking machine for gardening. As shown in FIG. 1 , the working machine2 is a hedge trimmer in the present embodiment. The working machine 2extends in a front-rear direction and is used for trimming highbranches. In the following description, in a state where the workingmachine 2 is placed on a placement surface P such as a ground surface(see FIG. 2 ), a longitudinal direction of the working machine 2 will betermed a front-rear direction of the working machine 2, a directionperpendicular to the placement surface P will be termed an up-downdirection of the working machine 2, and a direction perpendicular to thefront-rear direction and the up-down direction will be termed aleft-right direction of the working machine 2.

The working machine 2 comprises a support rod 10, a head unit 20, a gripunit 22, a rear unit 24, and a battery 4. The head unit 20, the supportrod 10, the grip unit 22, the rear unit 24, and the battery 4 arearranged in this order from the front toward the rear in the front-reardirection.

The support rod 10 extends in the front-rear direction. The support rod10 comprises a rod portion 12 and an attachment portion 14. The rodportion 12 has a substantially hollow cylindrical shape extending in thefront-rear direction. The rod portion 12 is a member that is gripped byan operator when the operator works with the working machine 2. Theattachment portion 14 is disposed at a front end of the rod portion 12.The attachment portion 14 is located at a front end of the support rod10. The attachment portion 14 has a shape that extends frontward fromthe front end of the rod portion 12 and then extends obliquely toward afront lower side.

As shown in FIG. 2 , the head unit 20 comprises a front tool 30, a headhousing 34, a motor 36, a power transmission mechanism 40, and a handle44. The front tool 30 comprises a pair of cutting blades 32 configuredto cut an object. The pair of cutting blades 32 extends in thefront-rear direction. The cutting blades 32 overlap each other in theup-down direction. The cutting blades 32 are configured to reciprocatein opposite phases relative to each other. Specifically, when one of thecutting blades 32 moves frontward, the other cutting blade 32 movesrearward, and when the one of the cutting blades 32 moves rearward, theother cutting blade 32 moves frontward. Each of the cutting blades 32comprises a plurality of blade edges 32 a arranged along the front-reardirection (see FIG. 1 ). When the cutting blades 32 reciprocate, hedgesand trees are trimmed by the plurality of blade edges 32 a.

The head housing 34 comprises a lower head housing 50 and an upper headhousing 52. The lower head housing 50 supports the pair of cuttingblades 32. The pair of cutting blades 32 extends frontward linearly fromthe lower head housing 50.

The upper head housing 52 is attached to a rear upper surface of thelower head housing 50. The upper head housing 52 houses the motor 36.The motor 36 is configured to drive the pair of cutting blades 32. Themotor 36 is, for example, a brushless motor.

A shaft 38 of the motor 36 extends within both the upper head housing 52and the lower head housing 50. The shaft 38 extends in the up-downdirection. The power transmission mechanism 40 is attached to a portionof the shaft 38 that is close to a lower end thereof. The powertransmission mechanism 40 is housed in the lower head housing 50. Thepower transmission mechanism 40 is attached to the pair of cuttingblades 32. The power transmission mechanism 40 is configured to transmitpower from the motor 36 to the pair of cutting blades 32 through a crankcam 42 of the power transmission mechanism 40. The power transmissionmechanism 40 is configured to convert rotary motion of the shaft 38 ofthe motor 36 to the reciprocal motion of the pair of cutting blades 32.Since the configuration of the power transmission mechanism 40 in hedgetrimmers is well known, the detailed description therefor is omitted.

The handle 44 is disposed on an upper front surface 52 a of the upperhead housing 52. In FIG. 2 , the upper front surface 52 a of the upperhead housing 52 is indicated by a broken line. The handle 44 is a memberto be gripped by the operator. The handle 44 extends frontward from theupper front surface 52 a of the upper head housing 52. The handle 44extends obliquely downward from its base end 44 a toward its front end44 b. The front end 44 b of the handle 44 is located below the base end44 a of the handle 44. The base end 44 a and the front end 44 b of thehandle 44 are located below a top portion 52 b that is located at ahighest position of the upper surface of the upper head housing 52. Thehandle 44 is located below a straight line X connecting the top portion52 b and a front end 30 a of the front tool 30. Here, the front end 30 aof the front tool 30 is a highest position of the front end 30 a of thefront tool 30. In FIG. 2 , the straight line X is indicated by a one-dotchain line.

The handle 44, from the base end 44 a to the front end 44 b, isseparated from an upper surface of the lower head housing 50. A distanceD1 between the handle 44 and the lower head housing 50 is, for example,20 mm or more. With the distance D1 of 20 mm or more between the handle44 and the lower head housing 50, the operator can insert his/herfinger(s) between the handle 44 and the lower head housing 50 to gripthe handle 44. The distance D1 between the handle 44 and the lower headhousing 50 may be 35 mm or more, and in the present embodiment, thedistance D1 is 50 mm. This enables the operator to more easily inserthis/her finger(s) between the handle 44 and the lower head housing 50.

Further, a length of the handle 44 from the base end 44 a to the frontend 44 b, that is, a length L1 of the handle 44 in the front-reardirection is, 25 mm or more, for example. With the length L1 of thehandle 44 in the front-rear direction being 25 mm or more, the operatorcan grip the handle 44 from right or left side with the multiplefingers, which enables the operator to stably grip the handle 44. Thelength L1 of the handle 44 in the front-rear direction may be 35 mm ormore, and in the present embodiment, the length L1 is 45 mm. This allowsthe operator to grip the handle 44 from the right or left side with morefingers.

As shown in FIG. 3 , a width W1 of the handle 44 in the left-rightdirection is 20 mm or more, for example. With the width W1 of the handle44 in the left-right direction being 20 mm or more, the operator canstably grip the handle 44 from front side or from above. The width W1 ofthe handle 44 in the left-right direction may be 35 mm or more, and inthe present embodiment, the width W1 is 35 mm. This allows the operatorto more stably grip the handle 44 from the front side or from above.

The head housing 34 further comprises a rotation unit 56. The rotationunit 56 is disposed at a rear end of the lower head housing 50. Therotation unit 56 is located at a rear end of the head unit 20. Therotation unit 56 is coupled to the attachment portion 14 of the supportrod 10. The rotation unit 56 is configured to rotate with respect to theattachment portion 14 about a rotation axis RA. Thus, the head unit 20rotates with respect to the support rod 10 about the rotation axis RA,which results in changes in rotation position of the head unit 20 withrespect to the support rod 10. The rotation axis RA extends in theleft-right direction. In FIG. 3 , the rotation axis RA is indicated by aone-dot chain line.

The rotation unit 56 comprises a pair of cover members 58 and a shaftmember 60. The cover members 58 are separated from each other in theleft-right direction. One of the cover members 58 is fixed to the rearend of the lower head housing 50, and the other cover member 58 isattached to the rear end of the lower head housing 50.

The shaft member 60 is interposed between the pair of cover members 58.A left end of the shaft member 60 is fixed to the left cover member 58,and a right end of the shaft member 60 is fixed to the right covermember 58. The shaft member 60 is supported by the pair of cover members58. The shaft member 60 has an elongated hollow cylindrical shapeextending in the left-right direction. A center axis of the shaft member60 in the left-right direction coincides with the rotation axis RA.

As shown in FIG. 4 , the attachment portion 14 comprises a first portion64, a second portion 66, and a third portion 68 at its front end. Thefirst portion 64, the second portion 66, and the third portion 68 arearranged in this order from right to left in the left-right direction.The first portion 64, the second portion 66, and the third portion 68each have a substantially hollow cylindrical shape of which center axisis the rotation axis RA. An outer circumferential surface of the secondportion 66 has a smaller diameter than an outer circumferential surfaceof the first portion 64. An outer circumferential surface of the thirdportion 68 has a smaller diameter than the outer circumferential surfaceof the second portion 66. Each of the outer circumferential surface ofthe first portion 64 (see FIG. 7 ) and the outer circumferential surfaceof the third portion 68 is partially notched.

As shown in FIG. 5 , the attachment portion 14 includes a through hole70. The through hole 70 is located at the front end of the attachmentportion 14. The through hole 70 is defined by inner circumferentialsurfaces of the first portion 64, the second portion 66, and the thirdportion 68. The through hole 70 extends in the left-right direction. Theshaft member 60 of the rotation unit 56 is inserted in the through hole70. Due to this, the rotation unit 56 rotates with respect to theattachment portion 14 about the rotation axis RA.

As shown in FIG. 3 , the rotation unit 56 further comprises apositioning plate 74. The positioning plate 74 is disposed between thecover members 58. The positioning plate 74 is fixed to the lower headhousing 50. The positioning plate 74 has a substantially hollowcylindrical shape that surrounds the outer circumferential surfaces ofthe second portion 66 and the third portion 68 of the attachment portion14 from outside (see FIG. 5 ).

The positioning plate 74 includes a plurality of positioning openings76. The positioning openings 76 penetrate the positioning plate 74 in athickness direction thereof. The positioning openings 76 are arrangedalong a circumferential direction of the positioning plate 74. As shownin FIG. 5 , the plurality of positioning openings 76 includes onefully-bent positioning opening 82 and a plurality of (six in the presentembodiment) operation positioning openings 78. The fully-bentpositioning opening 82 is disposed corresponding to a fully-bentposition P2 (see FIG. 9 ) that is used when the working machine 2 isstored. The fully-bent position P2 is a position used when the workingmachine 2 is stored. When the head unit 20 is in the fully-bent positionP2 with respect to the support rod 10, the head unit 20 is fully benttoward the support rod 10 as shown in FIG. 11 .

The plurality of operation positioning openings 78 is disposedcorresponding to an operation range P1 (see FIGS. 7 and 8 ) that is usedwhen the operator works with the working machine 2. When the head unit20 is within the operation range P1 with respect to the support rod 10,the head unit 20 is opened with respect to the support rod 10 as shownin FIGS. 1 and 10 . The operation positioning openings 78 are disposedat equal intervals in the circumferential direction of the positioningplate 74. The plurality of operation positioning openings 78 is disposedseparated from the fully-bent positioning opening 82. Hereinbelow, in arotation range of the head unit 20 about the rotation axis RA withrespect to the support rod 10, an operation positioning opening 78 thatis the farthest from the fully-bent positioning opening 82 may be termeda distant opening 78 a, an operation positioning opening 78 that is theclosest to the fully-bent positioning opening 82 may be termed aproximal opening 78 b, and the rest of the operation positioningopenings 78 disposed between the distant opening 78 a and the proximalopening 78 b may be termed intermediate openings 78 c.

The support rod 10 further comprises a position fixing mechanism 88. Theposition fixing mechanism 88 comprises an insertion member 90, a biasingmember 92, and a tension member 94. The insertion member 90 and thebiasing member 92 are disposed inside the attachment portion 14. Theinsertion member 90 has a pin shape comprising a head 90 a and a shaft90 b. The shaft 90 b of the insertion member 90 is inserted to any oneof the positioning openings 76. This enables the insertion member 90 tofix a rotation position of the support rod 10 with respect to the headunit 20 at various positions. Specifically, when the shaft 90 b of theinsertion member 90 is inserted to the fully-bent positioning opening82, the head unit 20 is fixed at the fully-bent position P2 with respectto the support rod 10 as shown in FIG. 9 . When the shaft 90 b of theinsertion member 90 is inserted to the distant opening 78 a, the headunit 20 is fixed at a distant operation position P11 with respect to thesupport rod 10 (see FIGS. 7 to 9 ). When the shaft 90 b of the insertionmember 90 is inserted to the proximal opening 78 b, the head unit 20 isfixed at a proximal operation position P12 with respect to the supportrod 10 as shown in FIG. 8 . That is, the insertion member 90 fixes thehead unit 20 at the fully-bent position P2 or within the operation rangeP1 (that is, in the region between the distant operation position P11and the proximal operation position P12) with respect to the support rod10. In the present embodiment, the proximal operation position P12corresponds to “operation position”.

As shown in FIG. 5 , the biasing member 92 is a coil spring, forexample. The biasing member 92 is configured to bias the shaft 90 b ofthe insertion member 90 toward the positioning openings 76. Thus, theposition fixing mechanism 88 keeps the shaft 90 b of the insertionmember 90 inserted to one of the positioning openings 76, in its normalstate.

The tension member 94 moves relatively to the support rod 10 in thefront-rear direction. The tension member 94 comprises a front portion 96and a rear portion 98. The front portion 96 is disposed inside theattachment portion 14. As shown in FIG. 6 , a front end 96 a of thefront portion 96 is branched into two parts separated from each other inthe left-right direction. The front end 96 a of the front portion 96interposes the shaft 90 b of the insertion member 90 between the twoparts, and is in contact with the head 90 a. The front portion 96supports the insertion member 90. The shaft 90 b can move between thetwo parts of the front end 96 a in a front upper direction and in a rearlower direction with respect to the tension member 94. Due to this, evenwhen the tension member 94 moves relatively to the support rod 10 in thefront-rear direction, the insertion member 90 can move together with thetension member 94. The rear portion 98 is disposed rearward of the frontportion 96. The rear portion 98 is gripped by the operator when thetension member 94 is moved relatively to the support rod 10 in thefront-rear direction. As shown in FIG. 5 , the rear portion 98 isdisposed outside of the attachment portion 14. The rear portion 98surrounds an outer circumferential surface of the rod portion 12 at afront end thereof.

In the normal state, the shaft 90 b of the insertion member 90 isinserted in one of the positioning openings 76 by the biasing force ofthe biasing member 92. In this state, the head unit 20 cannot rotateabout the rotation axis RA with respect to the support rod 10. Aposition of the tension member 94 in this state will be termed a fixingposition. When the tension member 94 moves relatively rearward beyondthe fixing position toward the rod portion 12, the insertion member 90moves in a radially outer direction of the rotation axis RA, whichresults in removal of the shaft 90 b of the insertion member 90 from thepositioning opening 76. With the shaft 90 b removed from the positioningopening 76, the head unit 20 can rotate about the rotation axis RA withrespect to the support rod 10. A position of the tension member 94 inthis state will be termed a movable position. In the present embodiment,the operator pulls the tension member 94 with his/her one hand from thefixing position to the movable position, so that the operator can rotatethe head unit 20, with his/her other hand, to the fully-bent position P2or within the operation range P1 with respect to the support rod 10. Theoperator can fix the head unit 20 with respect to the support rod 10 byreturning the tension member 94 from the movable position to the fixingposition.

As shown in FIG. 7 , the working machine 2 further includes a resistancemember 102. The resistance member 102 is interposed between the firstportion 64 of the attachment portion 14 and the lower head housing 50.The resistance member 102 is in contact with both the first portion 64and the lower head housing 50. The resistance member 102 is fitted tothe rear end of the lower head housing 50. The resistance member 102protrudes outward (that is, rearward) from the rear end of the lowerhead housing 50. The resistance member 102 has a substantially solidcylindrical shape extending in the left-right direction. The resistancemember 102 is constituted of an elastic material, for example, and inthe present embodiment, the resistance member 102 is constituted of arubber material. The resistance member 102 is configured to deform whenan external force is applied thereto, and restore to its original shapewhen the external force is removed. The resistance member 102 provides africtional force against the first portion 64 of the attachment portion14 when the head unit 20 rotates about the rotation axis RA with respectto the support rod 10. Thus, the resistance member 102 provides africtional force against the rotation of the head unit 20 with respectto the support rod 10. Hereinbelow, the frictional force provided by theresistance member 102 will be termed a resistance force.

When the head unit 20 rotates about the rotation axis RA with respect tothe support rod 10, the resistance member 102 moves on the outercircumferential surface of the first portion 64. As shown in FIGS. 7 and8 , while the head unit 20 rotates within the operation range P1 withrespect to the support rod 10, the resistance member 102 moves between adistant position C11 and a proximal position C12 on the outercircumferential surface of the first portion 64. As shown in FIG. 9 ,when the head unit 20 is at the fully-bent position P2 with respect tothe support rod 10, the resistance member 102 is at a contactingposition C2 on the outer circumferential surface of the first portion64. The distant position C11 is a position on the outer circumferentialsurface of the first portion 64 that the resistance member 102 is incontact with when the head unit 20 is at the distant operation positionP11 with respect to the support rod 10. The proximal position C12 is aposition on the outer circumferential surface of the first portion 64that the resistance member 102 is in contact with when the head unit 20is at the proximal operation position P12 with respect to the supportrod 10. The contacting position C2 is a position on the outercircumferential surface of the first portion 64 that the resistancemember 102 is in contact with when the head unit 20 is at the fully-bentposition P2 with respect to the support rod 10.

A distance between the outer circumferential surface of the firstportion 64 and the rotation axis RA is constant between the distantposition C11 and the proximal position C12, and the distance graduallyincreases from the proximal position C12 to the contacting position C2.A distance between the inner circumferential surface of the firstportion 64 and the rotation axis RA is constant all along acircumferential direction of the rotation axis RA. Thus, a thickness ofthe first portion 64 (that is, a dimension of the first portion 64 inthe radial direction of the rotation axis RA) is constant between thedistant position C11 and the proximal position C12, and the thicknessincreases from the proximal position C12 to the contacting position C2.

A gap G is provided at a position between the first portion 64 and thelower head housing 50 where the resistance member 102 is interposed. Thegap G is constant while the head unit 20 is within the operation rangeP1 with respect to the support rod 10 (that is, while the resistancemember 102 moves between the distant position C11 and the proximalposition C12 on the outer circumferential surface of the first portion64). Thus, while the head unit 20 rotates within the operation range P1with respect to the support rod 10, a degree of the deformation of theresistance member 102 is substantially constant, and the resistanceforce provided by the resistance member 102 against the first portion 64is substantially constant. As a result, while the head unit 20 rotateswithin the operation range P1 with respect to the support rod 10, theresistance force provided by the resistance member 102 is substantiallyconstant.

The gap G constantly becomes smaller, as the head unit 20 rotates fromthe proximal operation position P12 toward the fully-bent position P2(that is, as the resistance member 102 moves from the proximal positionC12 toward the contacting position C2 on the outer circumferentialsurface of the first portion 64). The gap G is the smallest when thehead unit 20 is at the fully-bent position P2 with respect to thesupport rod 10, and the gap G barely exists as shown in FIG. 9 . Thus,as the head unit 20 rotates from the proximal operation position P12toward the fully-bent position P2 with respect to the support rod 10,the degree of the deformation of the resistance member 102 increases andthe resistance force provided by the resistance member 102 against thefirst portion 64 increases. As a result, the resistance force providedby the resistance member 102 constantly increases, as the head unit 20rotates from the proximal operation position P12 toward the fully-bentposition P2 with respect to the support rod 10, and the resistance forceis the largest when the head unit 20 is at the fully-bent position P2with respect to the support rod 10.

As shown in FIG. 12 , the head unit 20 further comprises a positionsensor 104. Regarding the configuration of the head unit 20, FIG. 12shows only the position sensor 104. Although not shown, the positionsensor 104 is attached to the rear end of the lower head housing 50. Theposition sensor 104 is connected to a control board 130, which will bedescribed later. The position sensor 104 is configured to detect therotation position of the head unit 20 with respect to the support rod10. When the head unit 20 rotates about the rotation axis RA withrespect to the support rod 10, the position sensor 104 moves in adirection along the outer circumferential surface of the third portion68 of the support rod 10. As shown in FIG. 12 , while the head unit 20is within the operation range P1 with respect to the support rod 10, adetection piece 104 a of the position sensor 104 is in contact with thethird portion 68 of the attachment portion 14 of the support rod 10 andis thereby pressed in. In this state, the position sensor 104 outputs anon-signal to the control board 130, and the control board 130 therebyallows actuation of the motor 36. On the other hand, as shown in FIG. 13, when the head unit 20 is at the fully-bent position P2 with respect tothe support rod 10, the detection piece 104 a of the position sensor 104is separated from the third portion 68 and is not pressed in. In thisstate, the position sensor 104 outputs an off-signal to the controlboard 130, and the control board 130 thereby prohibits the actuation ofthe motor 36. Thus, it can be prevented that the motor 36 isaccidentally actuated and the pair of cutting blades 32 is therebydriven when the head unit 20 is fully bent toward the support rod 10.

As shown in FIG. 14 , the grip unit 22 is attached to a rear end of therod portion 12 of the support rod 10. The grip unit 22 comprises a griphousing 106, a trigger 108, a detection sensor 110, a lever 114, and apresence sensor 116. The grip housing 106 is a member configured to begripped by the operator with the other hand than the hand with which theoperator grips the rod portion 12 of the support rod 10 when theoperator uses the working machine 2 for work. The grip housing 106 isconstituted of a resin material in a shape that covers an outercircumferential surface of the support rod 10. The support rod 10 doesnot penetrate through the grip housing 106 and is attached to the griphousing 106.

The grip housing 106 comprises a left grip housing 106 a (see FIG. 1 )and a right grip housing 106 b. The left grip housing 106 a defines anouter shape of a left-half surface of the grip housing 106, and theright grip housing 106 b defines an outer shape of a right-half surfaceof the grip housing 106. The left grip housing 106 a and the right griphousing 106 b interpose the support rod 10 therebetween.

A power switch 120 and a display lamp 122 are disposed on a front uppersurface of the grip housing 106. The power switch 120 is a switch forswitching the working machine 2 between an on-state and an off-state.The display lamp 122 is configured to light up when the working machine2 is in the on-state and go off when the working machine 2 is in theoff-state.

The trigger 108 is attached to a lower surface of the grip housing 106.The trigger 108 is disposed rearward of the power switch 120 and thedisplay lamp 122. The trigger 108 is a member with which the operatorperforms on/off operation for the motor 36. The trigger 108 rotatesabout an axis A1 extending in the left-right direction.

The detection sensor 110 is attached inside the grip housing 106. Thedetection sensor 110 is connected to the control board 130, which willbe described later. The detection sensor 110 comprises a detection piece110 a. When the trigger 108 is pressed in by the operator, the trigger108 rotates and the detection piece 110 a is thereby pressed. In thisstate, the detection sensor 110 outputs an on-signal to the controlboard 130 and the control board 130 thus actuates the motor 36. On theother hand, in a state where the trigger 108 is not pressed in by theoperator, the trigger 108 is separated from the detection piece 110 a.In this state, the detection sensor 110 outputs an off-signal to thecontrol board 130 and the control board 130 thus stops the motor 36.

The lever 114 is attached to the upper surface of the grip housing 106.As shown in FIG. 15 , the lever 114 comprises a shark fin 114 a and anengagement member 114 b. The shark fin 114 a is integrated with theengagement member 114 b. The shark fin 114 a is a portion configured tobe operated by the operator. The shark fin 114 a is configured to rotateabout an axis A2 extending in the left-right direction. In a state wherethe shark fin 114 a is not pressed in by the operator, the engagementmember 114 b is engaged with a distal end 108 a of the trigger 108. Inthis state, the operator is prohibited from pressing in the trigger 108.On the other hand, when the shark fin 114 a is pressed in by theoperator, the engagement member 114 b separates from the distal end 108a of the trigger 108, which allows the operator to press in the trigger108. The operator can perform an operation of actuating the motor 36 bypressing the shark fin 114 a in with the palm of one hand and pressingthe trigger 108 in with the finger of the same hand.

As shown in FIG. 14 , the presence sensor 116 is attached inside thegrip housing 106. The presence sensor 116 is connected to the controlboard 130, which will be described later. The presence sensor 116 isconfigured to detect whether or not the operator is gripping the griphousing 106. In the present embodiment, the shark fin 114 a presses aswitch 116 a of the presence sensor 116 when the operator grips the griphousing 106 and presses the shark fin 114 a in with his/her palm, basedon which the presence sensor 116 detects the grip by the operator on thegrip housing 106. In this case, the presence sensor 116 outputs anon-signal to the control board 130, and the control board 130 thusallows the actuation of the motor 36. On the other hand, the shark fin114 a is separated from the switch 116 a of the presence sensor 116while the operator does not grip the grip housing 106 and does not pressthe shark fin 114 a in by the palm, thus the presence sensor 116 doesnot detect the grip by the operator on the grip housing 106. In thiscase, the presence sensor 116 outputs an off-signal to the control board130, and the control board 130 thus prohibits the actuation of the motor36.

As shown in FIG. 14 , the presence sensor 116 is disposed in an extendedregion that extends rearward from the rear end of the support rod 10. Asshown in FIG. 16 , in a rear plan view of the working machine 2, thepresence sensor 116 partially overlaps the support rod 10. In FIG. 16 ,the position of the support rod 10 is indicated by a one-dot chain line.

As shown in FIG. 14 , the rear unit 24 is disposed at a rear end of thegrip housing 106. The rear unit 24 comprises a rear housing 126 and acontrol unit 128. The rear housing 126 is disposed at the rear end ofthe grip housing 106. The rear housing 126 is constituted of a resinmaterial. The rear housing 126 comprises a left rear housing 126 a (seeFIG. 1 ) and a right rear housing 126 b. The left rear housing 126 adefines an outer shape of a left-half surface of the rear housing 126and is integrated with the left grip housing 106 a. The right rearhousing 126 b defines an outer shape of a right-half surface of the rearhousing 126 and is integrated with the right grip housing 106 b.

The control unit 128 is housed inside the rear housing 126. The controlunit 128 is disposed rearward of the rear end of the support rod 10. Thecontrol unit 128 is configured to control the actuation of the motor 36in accordance with operator's operations on the power switch 120, thetrigger 108, and the shark fin 114 a of the lever 114.

The control unit 128 comprises the control board 130 and a casing 132.The control board 130 comprises a plurality of switching elements (notshown) for controlling electric power to be supplied to the motor 36.The electric power is supplied to the motor 36 through a cable 136extending from the control board 130. The cable 136 extends through theinside of the rear housing 126, the inside of the grip housing 106, andthe inside of the support rod 10. The casing 132 fixes the control board130. The control unit 128 is in the extended region extending rearwardfrom the rear end of the support rod 10. The casing 132 extends in thefront-rear direction. As shown in FIG. 17 , in the rear plan view of theworking machine 2, the control board 130 and a front end 132 a and arear end 132 b (not shown in FIG. 17 ) of the casing 132 overlap thesupport rod 10. That is, in the rear plan view of the working machine 2,the control unit 128 partially overlaps the support rod 10. In FIG. 17 ,the position of the support rod 10 is indicated by a one-dot chain line.

As shown in FIG. 14 , the battery 4 is detachably attached to a rear endof the rear housing 126. The battery 4 is located at the rear end of theworking machine 2. The electric power from the battery 4 is supplied tothe respective constituent elements of the working machine 2 via thecontrol board 130. The battery 4 is in the extended region extendingrearward from the rear end of the support rod 10. As shown in FIG. 18 ,in the rear plan view of the working machine 2, the battery 4 overlapsthe support rod 10. In FIG. 18 , the position of the support rod 10 isindicated by a one-dot chain line.

In the rear plan view of the working machine 2, a gravity center CG ofthe working machine 2 is located within the range of the support rod 10.In FIG. 18 , the gravity center CG of the working machine 2 is indicatedby a black circle. Such placement of the gravity center CG of theworking machine 2 facilitates handling of the working machine 2 when theoperator uses the working machine 2.

The working machine 2 of the embodiment is an electric working machine.The working machine 2 comprises the support rod 10, the head unit 20,the position fixing mechanism 88, and the resistance member 102. Thesupport rod 10 extends in the front-rear direction and comprises theattachment portion 14 located at the front end of the support rod 10.The head unit 20 comprises the front tool 30, the motor 36 configured todrive the front tool 30, and the head housing 34 supporting the fronttool 30 and coupled to the attachment portion 14 rotatably about therotation axis. As shown in FIG. 5 , the position fixing mechanism 88 isconfigured to fix the rotation position of the head unit 20 with respectto the support rod 10. As shown in FIG. 7 , the resistance member 102 isinterposed between the attachment portion 14 and the head housing 34 inthe direction perpendicular to the rotation axis RA. The resistancemember 102 is configured to provide a resistance force against therotation of the head unit 20 with respect to the support rod 10.

According to the above configuration, the resistance member 102 providesthe resistance force when the head unit 20 rotates with respect to thesupport rod 10, thus the rotation of the head unit 20 with respect tothe support rod 10 is suppressed. This prevents the head unit 20 frombeing sharply bent toward the support rod 10. Thus, it is prevented thatthe operator inadvertently has his/her hand caught between the head unit20 and the support rod 10, for example.

Further, since the resistance member 102 is interposed between theattachment portion 14 and the head housing 34 in the directionperpendicular to the rotation axis RA, a larger resistance force isprovided as compared to a configuration in which the resistance member102 is interposed between members in a direction along the rotation axisRA, like a disk spring, for example. This more surely prevents the headunit 20 from being sharply bent with respect to the support rod 10.

The magnitude of the resistance force changes, as the rotation positionof the head unit 20 with respect to the support rod 10 changes.

In general, if the resistance force provided by the resistance member102 is constantly large, the sharp bending of the head unit 20 towardthe support rod 10 can surely be prevented, however, the constantlylarge resistance force makes it difficult for the head unit 20 to rotatewith respect to the support rod 10 and makes the usability deteriorated.On the other hand, if the resistance force provided by the resistancemember 102 is constantly small, the head unit 20 easily rotates withrespect to the support rod 10, which provides improved usability,however, safety issues rise because the head unit 20 can be sharply benttoward the support rod 10. The above configuration can improve theusability while ensuring safety for the operator by changing themagnitude of the resistance force provided by the resistance member 102as needed.

As shown in FIGS. 7 to 9 , the rotation position of the head unit 20with respect to the support rod 10 changes between the full-bentposition P2 at which the head unit 20 is fully bent toward the supportrod 10 and the operation position P12 at which the head unit 20 isopened with respect to the support rod 10. The magnitude of theresistance force increases without decreasing, as the rotation positionof the head unit 20 with respect to the support rod 10 shifts from theoperation position P12 to the full-bent position P2.

The above configuration makes it more difficult for the head unit 20 torotate with respect to the support rod 10, as the head unit 10 shiftsfrom the operation position P12 toward the fully-bent position P2. Thus,the sharp bending of the head unit 20 toward the support rod 10 can moresurely be prevented when the head unit 20 rotates with respect to thesupport rod 10 from the operation position P2 to the fully-bent positionP12.

As shown in FIGS. 7 to 9 , the gap G between the attachment portion 14and the head unit 20 at a position where the resistance member 102 isinterposed changes, as the rotation position of the head unit 20 withrespect to the support rod 10 changes, so that the magnitude of theresistance force changes.

In the above configuration, the magnitude of the resistance forceprovided by the resistance member 102 can be changed with the simpleconfiguration of changing the gap between the attachment portion 14 andthe head unit 20.

The resistance member 102 is constituted of a rubber material.

In the above configuration, the resistance member 102 can provide theresistance force without damaging or wearing the attachment portion 14and the head housing 34.

The front tool 30 comprises the cutting blades 32 for cutting an object.

In the above configuration, the working machine 2 can be used as one ofa mower, a hedge trimmer, and a chain saw.

A working machine 2 comprises a support rod 10 extending in thefront-rear direction and a head unit 20 attached to the front end of thesupport rod 10. The head unit 20 comprises a front tool 30, a powertransmission mechanism 40, a head housing 34, and a handle 44. The powertransmission mechanism 40 is configured to transmit power to the fronttool 30. The head housing 34 houses the power transmission mechanism 40and is rotatably attached to the support rod 10. The handle 44 extendsfrontward from the head housing 34. The handle 44 is configured to begripped by the operator when the head housing 34 is rotated with respectto the support rod 10. As shown in FIG. 2 , the handle 44 is disposedbelow a top portion 52 b of the head housing 34 in the up-down directionperpendicular to the front-rear direction, in a state where the workingmachine 2 is placed on a placement surface.

According to the above configuration, in the event of an upper surfaceside of the head housing 34 colliding against the ground surface due tothe working machine 2 being dropped, the top portion 52 b of the headhousing 34 collides with the ground surface first, thus the handle 44can be suppressed from colliding with the ground surface. As a result,damage to the handle 44 can be prevented.

As shown in FIG. 2 , the handle 44 extends obliquely toward a frontlower side from the head housing 34 in the state where the workingmachine 2 is placed on the placement surface.

In general, application of an impact to the front end 44 b of the handle44 is likely to result in damage to the handle 44, as compared toapplication of an impact to the base end 44 a of the handle 44. In theabove configuration, the front end 44 b of the handle 44 is locatedlower than the base end 44 a of the handle 44. Due to this, in the eventof the upper surface side of the head housing 34 colliding against theground surface due to the working machine 2 being dropped, the base end44 a of the handle 44 collides with the ground surface before the frontend 44 b of the handle 44. As a result, damage to the handle 44 can besuppressed even when the handle 44 collides with the ground surface.

As shown in FIG. 2 , the handle 44 is located below a line connectingthe top portion 52 b of the head housing 34 and the front end 30 a ofthe front tool 30 in the state where the working machine 2 is placed onthe placement surface.

In the above configuration, in the event of the upper surface side ofthe head housing 34 colliding against the ground surface due to theworking machine 2 being dropped, the top portion 52 b of the headhousing 34 and the front end 30 a of the front tool 30 collide with theground surface first, thus the handle 44 does not collide with theground surface. Due to this, damage to the handle 44 can surely beprevented.

As shown in FIG. 2 , the length L1 of the handle 44 in the front-reardirection is 25 mm or more.

When rotating the head housing 34 with respect to the support rod 10,the operator grips the handle 44 with his/her hand. According to theabove configuration, the operator can grip the handle 44 from right sideor left side with his/her multiple fingers.

As shown in FIG. 3 , the width W1 of the handle in the left-rightdirection perpendicular to the front-rear direction and the up-downdirection is 20 mm or more.

When rotating the head housing 34 with respect to the support rod 10,the operator grips the handle 44 with his/her hand. According to theabove configuration, the operator can stably grip the handle 44 fromfront side or from above.

As shown in FIG. 2 , the head housing 34 comprises the lower headhousing 50 supporting the front tool 30 and the upper head housing 52disposed above the lower head housing 50. The handle 44 extendsfrontward from the upper head housing 52. The handle 44 is apart by 20mm or more from the lower head housing 50.

When rotating the head housing 34 with respect to the support rod 10,the operator grips the handle 44 with his/her hand. The aboveconfiguration allows the operator to insert his/her finger(s) betweenthe front end 44 b of the handle 44 and the lower head housing 50 togrip the handle 44.

A working machine 2 is an electric working machine. The working machine2 comprises a support rod 10, a head unit 20, and a grip unit 22. Thesupport rod 10 extends in the front-rear direction. The head unit 20 isattached to the front end of the support rod 10 and comprises a fronttool 30 and a motor 36 configured to drive the front tool 30. The gripunit 22 is attached to the rear end of the support rod 10. As shown inFIG. 14 , the grip unit 22 comprises a grip housing 106, a detectionsensor 110, and a presence sensor 116. The grip housing 106 isconfigured to be gripped by the operator. The detection sensor 110 isattached to the grip housing 106 and is configured to detect an on/offoperation for the motor 36 by the operator. The presence sensor 116 isattached to the grip housing 106 and is configured to detect a grip bythe operator on the grip housing 106. The support rod 10 does notpenetrate through the grip housing 106. As shown in FIG. 16 , in therear plan view of the working machine 2, at least one of the detectionsensor 110 and the presence sensor 116 may at least partially overlapthe support rod 10.

According to the above configuration, in the rear plan view of theworking machine 2, the entirety of the detection sensor 110 and theentirety of the presence sensor 116 both do not have to be disposedoutside a region overlapping the support rod 10. Due to this, theconfiguration can make the grip housing 106 slim, thus it can make thegrip unit 22 slim, as compared to a configuration in which the entiretyof the detection sensor 110 and the entirety of the presence sensor 116both do not overlap the support rod 10 in the rear plan view of theworking machine 2.

The grip unit 22 further comprises a lever 114. The lever 114 isattached to the grip housing 106 and is configured to be operated by theoperator. The presence sensor 116 is configured to detect the grip bythe operator on the grip housing 106 when the lever 114 is operated.

In the above configuration, the presence sensor 116 detects the grip bythe operator on the grip housing 106 without the operator directlytouching the presence sensor 116. Thus, the presence sensor 116 can bedisposed at a position within the grip housing 106 that the operatorwould not directly touch.

The working machine 2 further comprises a control unit 128 disposedrearward of the rear end of the support rod 10 and configured to controlactuation of the motor 36. As shown in FIG. 17 , in the rear plan viewof the working machine 2, the control unit 128 at least partiallyoverlaps the support rod 10.

According to the above configuration, in the rear plan view of theworking machine 2, the entirety of the control unit 128 does not have tobe disposed outside the region overlapping the support rod 10. Thus, theconfiguration can reduce the size of the working machine 2 in thedirection perpendicular to the front-rear direction, as compared to aconfiguration in which the entirety of the control unit 128 does notoverlap the support rod 10 in the rear plan view of the working machine2.

The front tool 30 comprises the cutting blades 32 for cutting an object.

In the above configuration, the working machine 2 can be used as one ofa mower, a hedge trimmer, and a chain saw.

Second Embodiment

A second embodiment will be described with reference to FIG. 19 . Forthe second embodiment, differences from the first embodiment will bedescribed, and the same features as those of the first embodiment willbe denoted with the same reference signs and descriptions thereof willbe omitted. In the second embodiment, the distance between the outercircumferential surface of the first portion 64 and the rotation axis RAdiffers from that of the first embodiment. The distance between theouter circumferential surface of the first portion 64 and the rotationaxis RA is constant between the distant position C11 and the proximalposition C12. Further, the distance between the outer circumferentialsurface of the first portion 64 and the rotation axis RA increases fromthe proximal position C12 toward an intermediate position C3 and thendecreases from the intermediate position C3 toward the contactingposition C2. The thickness of the first portion 64 is constant betweenthe distant position C11 and the proximal position C12, increases fromthe proximal position C12 toward the intermediate position C3 and thendecreases from the intermediate position C3 toward the contactingposition C2.

The gap G between the first portion 64 and the lower head housing 50becomes smaller from the proximal position C12 toward the intermediateposition C3 and then becomes larger from the intermediate position C3toward the contacting position C2. That is, the gap G decreases and thenincreases as the head unit 20 moves from the proximal operation positionP12 toward the fully-bent position P2 with respect to the support rod10. Thus, the degree of the deformation of the resistance member 102increases and then decreases, as the head unit 20 moves from theproximal operation position P12 toward the fully-bent position P2 withrespect to the support rod 10. As a result, the resistance forceprovided by the resistance member 102 increases and then decreases, asthe head unit 20 moves from the proximal operation position P12 towardthe fully-bent position P2 with respect to the support rod 10.

In the present embodiment, the rotation position of the head unit 20with respect to the support rod 10 changes between the full-bentposition P2 at which the head unit 20 is fully bent toward the supportrod 10 and the operation position P12 at which the head unit 20 isopened with respect to the support rod 10. The magnitude of theresistance force decreases after having increased, as the rotationposition of the head unit 20 with respect to the support rod 10 shiftsfrom the operation position P12 to the full-bent position P2.

The above configuration makes it difficult for the head unit 20 torotate with respect to the support rod 10 as the head unit 20 shiftsfrom the operation position P12 toward a vicinity of the fully-bentposition P2, while the configuration makes it easier for the head unit20 to rotate with respect to the support rod 10 in the vicinity of thefully-bent position P2. Thus, the configuration can prevent the sharpbending of the head unit 20 toward the support rod 10 when the head unit20 rotates from the operation position P12 toward the fully-bentposition P2, and also can facilitate the bending of the head unit 20toward the support rod 10 in the vicinity of the fully-bent position P2.

In one aspect of the working machine 2, the head unit 20 may comprise anattachment portion attached to the support rod 10, and the support rod10 may comprise a rotation unit configured to rotate with respect to thehead unit 20.

In one aspect of the working machine 2, the position fixing mechanism 88may not fix the rotation position of the support rod 10 with respect tothe head unit 20 at the predetermined positions, but may rather beconfigured to fix the head unit 20 at any positions with respect to thesupport rod 10.

In one aspect of the working machine 2, the positioning plate 74 mayinclude a plurality of positioning recesses that are depressed from anouter circumferential surface of the positioning plate 74. In this case,the plurality of positioning recesses does not penetrate the positioningplate 74 in the thickness direction.

In one aspect of the working machine 2, the resistance member 102 may befitted to the first portion 64 of the attachment portion 14 of thesupport rod 10.

In one aspect of the working machine 2, when the head unit 20 rotateswith respect to the support rod 10 from the proximal operation positionP12 toward the fully-bent position P2, the gap G may be constant fromthe proximal operation position P12 to a predetermined position anddecrease from the predetermined position toward the fully-bent positionP2. In this case, when the head unit 20 rotates with respect to thesupport rod 10 from the proximal operation position P12 toward thefully-bent position P2, the resistance force may be constant from theproximal operation position P12 to the predetermined position anddecrease from the predetermined position toward the fully-bent positionP2.

In one aspect of the working machine 2, the handle 44 may extend fromthe upper front surface 52 a of the upper head housing 52 in a directionalong the front-rear direction.

In one aspect of the working machine 2, the presence sensor 116 may notoverlap the support rod 10 and the detection sensor 110 may at leastpartially overlap the support rod 10 in the rear plan view of theworking machine 2.

In one aspect of the working machine 2, both the detection sensor 110and the presence sensor 116 may at least partially overlap the supportrod 10 in the rear plan view of the working machine 2.

In one aspect of the working machine 2, the presence sensor 116 may be apressure sensor that is configured to detect a pressure applied by thegrip of the operator on the grip housing 106 and detect the grip by theoperator on the grip housing 106 from the detected pressure. Further,the presence sensor 116 may be an optical detection sensor. In thiscase, the optical detection sensor may be configured to sense an amountof light reflection or may be configured to sense an amount of lightpassing through a space. Alternatively, the presence sensor 116 may be astatic capacitance sensor disposed on the surface of the grip housing106.

In one aspect of the working machine 2, the working machine 2 may be achain saw or a mower.

In one aspect of the working machine 2, the motor 36 may be disposed atthe rear end of the support rod 10.

In one aspect of the working machine 2, the working machine 2 maycomprise an engine, instead of the motor 36.

In one aspect of the working machine 2, the motor 36 may be a brushmotor.

What is claimed is:
 1. An electric working machine, comprising: asupport rod extending in a front-rear direction and having a front end;a head unit comprising: a front tool; a motor mechanically connected tothe front tool and configured to drive the front tool; and a headhousing supporting the front tool and the motor and coupled to the frontend of the support rod rotatably about a rotation axis; a positionfixing mechanism disposed at one of the support rod and the head unitand configured to fix a rotation position of the head unit with respectto the support rod; and a resistance member interposed between the frontend of the support rod and the head housing with respect to a directionperpendicular to the rotation axis, the resistance member beingconfigured to provide a resistance force against rotation of the headunit with respect to the support rod.
 2. The electric working machineaccording to claim 1, wherein as the rotation position of the head unitwith respect to the support rod changes, a degree of deformation of theresistance member changes so that a magnitude of the resistance forcechanges.
 3. The electric working machine according to claim 2, whereinthe rotation position of the head unit with respect to the support rodchanges between a full-bent position at which the head unit is fullybent toward the support rod and an operation position at which the headunit is opened with respect to the support rod, and as the rotationposition of the head unit with respect to the support rod shifts fromthe operation position to the full-bent position, the degree of thedeformation of the resistance member increases without decreasing sothat the magnitude of the resistance force increases without decreasing.4. The electric working machine according to claim 2, wherein therotation position of the head unit with respect to the support rodchanges between a full-bent position at which the head unit is fullybent toward the support rod and an operation position at which the headunit is opened with respect to the support rod, and as the rotationposition of the head unit with respect to the support rod shifts fromthe operation position to the full-bent position, the degree of thedeformation of the resistance member decreases after having increased sothat the magnitude of the resistance force decreases after havingincreased.
 5. The electric working machine according to claim 2, whereinas the rotation position of the head unit with respect to the supportrod changes, a gap between the front end of the support rod and the headunit housing at a position where the resistance member is interposedchanges, by which the degree of the deformation of the resistance memberchanges so that the magnitude of the resistance force changes.
 6. Theelectric working machine according to claim 1, wherein the resistancemember is constituted of a rubber material.
 7. The electric workingmachine according to claim 1, wherein the front tool comprises a cuttingblade for cutting an object.